What is a key limitation of MIL-H-5606 hydraulic fluid?

MIL-H-5606 hydraulic fluid is known for its flammable properties, which is a significant limitation when it comes to its use in aviation and other critical applications. This type of fluid is derived from petroleum and has a relatively low flash point, making it susceptible to ignition under certain conditions.

When handling or operating systems that utilize this hydraulic fluid, it's crucial to implement strict safety measures to minimize the risk of fire. This includes ensuring proper maintenance of hydraulic systems, avoiding leaks, and ensuring that fluid is not exposed to heat sources.

The other considerations regarding the fluid, such as potential corrosive properties or compatibility with seals, while important, do not directly address the immediate fire risk presented by its flammability. Those factors can complicate system design but do not present an immediate hazard in the operational sense as flammability does.